The present invention relates digital data processing devices, and, in particular, to methods and apparatus for powering such devices with internal power supplies. The invention has particular application in compact, xe2x80x9clow profilexe2x80x9d devices where space is at a premium and where overheating is of concern.
The components within a digital data processing apparatus require electricity at various defined voltages, such as 3.3, 5, or 12 volts, for their operation, and a number of these components such as standard CD-ROMs and microprocessor chips require substantial power, e.g., twenty to forty watts of power. This power is generally provided by one or more internal power supplies mounted on the device chassis. These convert 110-115 or 220-230 volt alternating current (AC) signal into lower voltage direct current (DC) potentials, supplying the DC drive signals through a number of output terminals at the different levels required by the respective components.
According to the prior art, power generated by an internal supply is typically routed to other components of a device via electrical cables having one or more cable connectors, e.g., plugs or sockets. While this is adequate for many applications, it can prove problematic when internal space is at a premium and, specifically, where heat build-up is a concern. In addition to being difficult to insert and route cabling within a tightly packed device chassis, cables can obstruct the internal air flow. Though cables can sometimes be re-routed and fans can be used to compensate for such blockage, the tendency toward more densely packed circuitry and lower profile devices challenges one""s ability to rely on cable connections and renders cable routing problematic. The integrity of such cables and their connectors, moreover, may suffer from flexing, abrasion or loosening if the chassis is repeatedly opened or the cables are frequently jarred.
One area of particular concern arises for web servers, wherein racks or cabinets may hold many, e.g., tens or hundreds, of closely-packed substantially identical communications and data storage units in a small space, each with their associated support cards and one or more power supplies. Such cabinets may have one, two, three or more vertical stacks of the units, and may be packed ten or more high. Each unit may reside in a closed box-like chassis or covered tray unit that slides drawer-like into the rack. These chassis have a standard width (e.g., 19 inches) and a standardized height (1U, 2U or 3U), and the rack may possess threaded securing holes spaced every inch or so along its front face for bolting the chassis into the rack.
The problems of effectively cooling such devices and arranging internal cabling are particularly severe for 1U size rack-mounted storage arrays, in which CD ROMS or memory units must be powered by and connected to a power supply that sits with the CD ROMS in a slide-in assembly barely two inches tall. Since cooling air must circulate through the unit, the provision of cabling to interconnect the power supplies with driver devices may impede air-flow. Cables may also be subject to loosening, or to wear or abrasion from flexing into contact with the walls or the cover plate of such a unit.
One object of the present invention is to provide an improved digital data storage apparatus and methods.
A more particular object is to provide such apparatus and methods as are particularly adapted to web servers and other data processing apparatus that are compact of design and/or intolerant of overheating.
A still further object is to provide such apparatus and methods as can be implemented at low cost.
A still further object of the invention is to provide such apparatus and methods as can be adapted to pre-existing equipment, as well as designed for use in new equipment.
One or more of the aforementioned objects are met by the present invention which provides, in one aspect, a digital data processing device such as, by way of non-limiting example a network or web server device, having a power supply, at least one component, e.g. a motherboard or a disk drive, and a power transfer element. The power transfer element provides electrical coupling between the power supply and the component and, as such, can serve in the place of conventional wires or cables. It comprises a substantially rigid power transfer card, e.g. a circuit card, with at least one conductive pathway. The power transfer element, according to one aspect of the invention, is not integral to either the power supply or the component, though it is adapted to physically mate with them to provide electrical coupling. Preferably, the number of pathways on the power transfer card is large, increasing with the amount of power to be coupled, and the pathways connect at one end to a smaller number of lands.
Further aspects of the invention provide mechanisms for coupling the power transfer element to the supply and the other component. For example, the power supply can comprise an edge card on which are disposed conductive pathways or vias carrying output power. The transfer element, correspondingly, can comprise an adapter or edge connector mounted on the power transfer card and matable with the edge card of the power supply.
By way of further example, the power transfer element may also include, or be adapted for use with, a fastening mechanism that provides physical and electrical coupling between the lands of the power transfer card and a component. The fastening element can be, e.g., a screw or a screw and spacer or other one-to-one connector, that provides removable physical and electrical coupling between the substantially rigid power transfer card and a circuit board in the powered component. At least one aperture can be provided in the card for receiving the fastening element and for transferring power from the conductive pathways to the component circuit board.
In another embodiment, the present invention is directed to a power transfer system comprising a power supply having an edge card, an edge connector adapted to mate with the edge card and carried by a substantially rigid power transfer card that has a plurality of conductive power pathways, a component having a circuit board, and a power-coupling fastening element for removably and conductively securing the power transfer card to the circuit board. The connector and the card carry power from the power supply to the component, and the mounting and connecting arrangement assure that the power is carried along a rigid, non-flexing conductive array lying in a plane parallel to, and generally offset from one or both or the boards to which it connects. One or both of the power supply edge card, and the power transfer card may employ multiple parallel conductive paths to carry substantial currents without the need for wires or cables, and multiple paths may connect to a common, high current capacity fastening element.
The present invention has several advantages over the prior art. Among these is that it eliminates the need for cables or flexing elements to transfer power from the power supply to the component. In particular embodiments, the power transfer card may be positioned parallel to, but offset from one or both of the device board and the power supply board. The conductive fastening elements may be metal stand-offs or column-like pedestals. This can improve airflow within the chassis and eliminate the need for complex wire routings. These advantages are particularly relevant for digital data processing apparatus, such as servers, where space is constrained, movable chassis covers may jar loose wires, and the components are particularly sensitive to accumulating internally-generated heat.